Re: pgstattuple: Use streaming read API in pgstatindex functions

Hi,

On Mon, Oct 13, 2025 at 5:42 PM Nazir Bilal Yavuz <byavuz81(at)gmail(dot)com> wrote:
>
> Hi,
>
> On Mon, 13 Oct 2025 at 11:42, Xuneng Zhou <xunengzhou(at)gmail(dot)com> wrote:
> >
> > Here is patch v3. The comments have been added, and the extra scope
> > ({}) has been removed as suggested.
>
> Thanks, the code looks good to me!
>
> The benchmark results are nice. I have a quick question about the
> setup, if you are benchmarking with the default io_method (worker),
> then the results might show the combined benefit of async I/O and
> streaming I/O, rather than just streaming I/O alone. If that is the
> case, I would suggest also running a benchmark with io_method=sync to
> isolate the performance impact of streaming I/O. You might get
> interesting results.

The previous benchmark was conducted using the default
io_method=worker. The following results are from a new benchmark run
with io_method=sync. The performance gains from streaming reads are
still present, though smaller than those observed when asynchronous
I/O and streaming I/O are combined — which is expected. Thanks for the
suggestion!

Fragmented Indexes (Cold Cache)

Index Type    Size  Baseline  Patched  Speedup
Primary Key    Medium  43.80 ms  38.61 ms  1.13×
Primary Key    Large  238.24 ms  202.47 ms  1.17×
Primary Key    XLarge  962.90 ms  793.57 ms  1.21×
Timestamp     Medium  33.34 ms  29.98 ms  1.11×
Timestamp     Large  190.41 ms  161.34 ms  1.18×
Timestamp     XLarge  794.52 ms  647.82 ms  1.22×
Float (score)   Medium  14.46 ms  13.51 ms  1.06×
Float (score)   Large  87.38 ms  77.22 ms  1.13×
Float (score)   XLarge  278.47 ms  233.22 ms  1.19×
Composite (3 col) Medium  44.49 ms  40.10 ms  1.10×
Composite (3 col) Large  244.86 ms  211.01 ms  1.16×
Composite (3 col) XLarge  1073.32 ms  872.42 ms  1.23×

________________________________

Fragmented Indexes (Warm Cache)

Index Type    Size  Baseline  Patched  Speedup
Primary Key    Medium  7.91 ms  7.88 ms  1.00×
Primary Key    Large  35.58 ms  36.41 ms  0.97×
Primary Key    XLarge  126.29 ms  126.95 ms  0.99×
Timestamp     Medium  5.14 ms  6.82 ms  0.75×
Timestamp     Large  22.96 ms  29.55 ms  0.77×
Timestamp     XLarge  104.26 ms  106.01 ms  0.98×
Float (score)   Medium  3.76 ms  4.18 ms  0.90×
Float (score)   Large  13.65 ms  13.01 ms  1.04×
Float (score)   XLarge  40.58 ms  41.28 ms  0.98×
Composite (3 col) Medium  8.23 ms  8.25 ms  0.99×
Composite (3 col) Large  37.10 ms  37.59 ms  0.98×
Composite (3 col) XLarge  139.89 ms  138.21 ms  1.01×

Best,
Xuneng